In recent years there has been increased interest in the use of biological probes, such as membrane potential sensitive dye materials,to determine changes in the membrane potential of living cells and/or other cellular structures in electrophysiological and biophysical studies of living cells. For example, such materials have been used to study membrane potential in squid giant axon cells, Cohen LPB et al. J. Membrane Biol. 19,1 (1974), in red blood cells, Hoffmann, J. R. and Laris, P. C., Physiol. Lond. 239, 519 (1974), and for frog heart muscular tissue, Morad, M. and Selema, G., J. Physiol. Lond. 292 267 (1972).
Along this same vein the study of blood cell physiology is leading to methods for detection of disease states in human and animal bodies. For example, we have developed a method for the early detection of cancer and other antigen producing disease and body conditions employing intracellular fluroescein fluorescence polarization measurements in living cells to study changes in the structuredness of cytoplasmic matrix (SCM). SCM includes various cell structures such as, for example, mitochondria, cell membranes, cell sap, lysosomes, ribosomes, nuclei and the like. Our method, which is referred to in literature as the "SCM-Test", and the technique employed is summarized in a publication by L. Cercek, B. Cercek, "Application of the Phenomenon of Changes in the Structuredness of Cytoplasmic Matrix (SCM) in the Diagnosis of Malignant Disorders: A Review", Europ. J. Cancer, Vol. 13, 903-915 (1977). Using our techniques, early diagnosis of cancer and other types of diseases and body conditions is readily accomplished by measuring the differential responses of a density specific subpopulation of peripheral blood lymphocytes to, for example, mitogen phytohaemagglutinin and to cancer associated antigens. Changes in intracellular fluorescein fluorescence polarization are used to indicate the differential responses of the lymphocytes.
The above described method, however, requires very highly skilled personnel and extremely careful techniques in order to separate and isolate the subpopulation of SCM-responding lymphocytes from the blood sample and to carry out the fluorescence measurements. In addition the SCM-Test technique demands microanalytical precision in the intracellular fluorescence polarization measurements, high instrument sensitivity and stability. Poor technique and unskilled handling of lymphocytes sensitive to perturbations of the metabolic state can result in unreproduceable, and totally erroneous test results.
Accordingly, it would be highly desirable to provide a screening technique for the detection of cancer which is simpler and less expensive to run and which can be reliably carried out with a lower degree of technical proficiency using readily available equipment thereby rendering the methodology of such a screening technique practical for routine use in clinical laboratories and even in the doctor's office.